Your Sports Bra Might Contain BPA

Researchers detected high levels of bisphenol A in sports bras and shirts, which raises concerns about adverse health effects.

woman in sports bra with headphones

Eugenio Marongiu / Getty Images

For many women, putting on a sports bra often indicates a pursuit of health. She might be heading out for a run or a hike or a gym class to elevate that heart rate or get some fresh air. But new research shows that the sports bra itself might be undermining health in an unexpected and disturbing way—through the very material it's made of.

Researchers at the Center for Environmental Health (CEH) tested eight brands of sports bras and six brands of athletic shirts. They found levels of bisphenol A (BPA) in the fabrics that could expose a wearer to up to 22 times the safe limit determined by California law.

BPA is a synthetic chemical made by petrochemical companies. Chemicals like benzene and propylene are synthesized to make phenol and acetone, which are common feedstocks for BPA. This goes into polyester-based clothing with spandex to promote dye retention, reduce static, and boost fire retardancy. But it has the undesirable side effect of also endangering human health.

Why BPA Is a Problem

As Dr. Jimena Díaz Leiva, science director at the CEH, explained to Treehugger over email,

"People are exposed to BPA through ingestion (e.g., from eating food or drinking water from containers that have leached BPA) or by absorption through skin (e.g., from handling receipt paper). Studies have shown that BPA can be absorbed through skin and end up in the bloodstream after handling receipt paper for seconds or a few minutes at a time. Sports bras and athletic shirts are worn for hours at a time, and you're meant to sweat in them, so it is concerning to be finding such high levels of BPA in our clothing."

In other words, sweating increases the potential to pull chemicals out of the fabric and into the body. 

BPA is a known hormone disruptor, a chemical that mimics estrogen and is believed to cause developmental and reproductive harm. It has been linked to various cancers, metabolic disorders, diabetes, and other serious health concerns, particularly in infants and toddlers. BPA can be ingested or enter into the body through the skin, known as dermal absorption. 

BPA can also adversely affect reproduction, growth, and development of both aquatic and terrestrial organisms; and while it's not technically a "persistent" chemical in the way that some others are, the fact that it's continuously released through human causes means it is frequently detected in the natural environment, thus earning it the descriptor of "pseudo-persistent."

Reformulations Needed

Díaz Leiva explained that this latest research stemmed from an earlier investigation into over 100 brands of polyester socks, which found levels of BPA to be as much as 33 times higher than the safe limit. She said, "We tested socks with different blends of polyester, cotton, and spandex and found significant amounts of BPA in socks made of a polyester/spandex blend. We did not find BPA in socks predominantly made from cotton or other natural fibers." 

CEH has put pressure on brands over the past year to reformulate their socks and remove all bisphenols, including BPA. Some have agreed to do so. 

Then CEH decided to test sports bras and athletic shirts—and, not surprisingly, came up with similar findings. Brands that were flagged include Nike, Athleta, PINK, Asics, The North Face, FILA, Brooks, All in Motion, Mizuno, New Balance, and Reebok.

"We are still learning how and why BPA is showing up in clothing, but we do know there is no need for this harmful chemical in our clothing. Companies should reformulate to remove all bisphenols," Díaz Leiva said. 

Sometimes reformulations mean removing BPA so that an item can be labeled as "BPA-free" and replacing it with other bisphenols (like BPS), which cause the same kind of harm, just under a different name. Therefore, it's best to stay away from all bisphenols.

What to Do

"We encourage you to limit your exposure or time wearing socks, sport bras, and athletic shirts from the brands on our list and to shop for clothing made from cotton, wool, or other natural fibers and when possible. If you wear polyester-based clothing with spandex, we recommend limiting the time you spend in your activewear by changing after your workout," Díaz Leiva told Treehugger.

As with the socks, sports bras and athletic shirts made from natural materials do not pose the same threat. They may not absorb moisture as well, but that is a worthwhile tradeoff. Some companies now offer sports bras and athletic shirts made from wool or cotton, with lower percentages of synthetic material, so check the tags when shopping; those might be a better option. BPA does not wash out over time, so buying secondhand is not a workaround for this problem, either. 

In the meantime you can sign the CEH's petition, urging athletic brands to eliminate bisphenols.